JPH1087309A - Production of rare earth element phosphate having small excess amount of phosphorus than stoichiometric amount - Google Patents
Production of rare earth element phosphate having small excess amount of phosphorus than stoichiometric amountInfo
- Publication number
- JPH1087309A JPH1087309A JP18496197A JP18496197A JPH1087309A JP H1087309 A JPH1087309 A JP H1087309A JP 18496197 A JP18496197 A JP 18496197A JP 18496197 A JP18496197 A JP 18496197A JP H1087309 A JPH1087309 A JP H1087309A
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- JP
- Japan
- Prior art keywords
- rare earth
- earth element
- aqueous solution
- phosphate
- phosphoric acid
- Prior art date
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Abstract
Description
【0001】[0001]
【発明の属する技術分野】本発明は、化学量論超過燐含
有量の低い希土類元素燐酸塩の製造方法に関する。[0001] The present invention relates to a method for producing a rare earth element phosphate having a low stoichiometric excess phosphorus content.
【0002】[0002]
【従来の技術】いくつかの混合希土類元素燐酸塩は陰極
線管用蛍光体の原料として(USP3507804号参照)、Li
−Nd−Yb燐酸塩は赤外線蛍光体の原料として(特開
昭53-60888号公報参照)、セリウムおよびテルビウムで
付活された単斜晶系正燐酸ランタンは3波長型蛍光ラン
プ用の蛍光体の原料として(USP3634282号および特開昭
54-56086号公報参照)知られている。これら蛍光体の原
料となる希土類元素燐酸塩の製造方法として、既に、本
発明者等は、燐酸水溶液と希土類元素の酸性水溶液の沈
澱反応を提案している。2. Description of the Related Art Some mixed rare earth phosphates are used as raw materials for phosphors for cathode ray tubes (see US Pat. No. 3,507,804).
-Nd-Yb phosphate is a raw material for an infrared phosphor (see JP-A-53-60888), and monoclinic lanthanum orthophosphate activated with cerium and terbium is a phosphor for a three-wavelength fluorescent lamp. (USP3634282 and JP
No. 54-56086). The present inventors have already proposed a precipitation reaction of a phosphoric acid aqueous solution and an acidic aqueous solution of a rare earth element as a method for producing a rare earth element phosphate serving as a raw material of these phosphors.
【0003】[0003]
【発明が解決しようとする課題】しかし、この方法で得
られる希土類元素燐酸塩は化学量論以上の過剰の燐分を
若干含むため、陰極線管や蛍光ランプにスラリーの形で
塗布する際に、この過剰の燐分がスラリー中に溶け出し
てスラリー中に含まれる有機バインダーの安定性ひいて
はスラリーの安定性に悪影響を及ぼしスラリーのゲル化
の原因となり、また蛍光ランプ中の水銀と徐々に反応し
て輝度の低下を引き起こすという欠点があった。化学量
論以上の過剰の燐分を低減する方法として、過剰の燐分
と反応する量の酸化物を加え、再度焼成する方法が提案
されたが(特開平5-171143号公報参照)、粉体混合のた
めに反応の不均一化が起こり易いという欠点があった。
本発明は、かかる欠点を解決した、化学量論超過燐含有
量の低い希土類元素燐酸塩の製造方法を新たに提供す
る。However, since the rare earth element phosphate obtained by this method contains a small amount of excess phosphorus in excess of the stoichiometric amount, it is difficult to apply the slurry to a cathode ray tube or a fluorescent lamp in the form of a slurry. This excess phosphorus dissolves into the slurry and adversely affects the stability of the organic binder contained in the slurry and, consequently, the stability of the slurry, causing gelation of the slurry and gradually reacting with mercury in the fluorescent lamp. This causes a decrease in luminance. As a method for reducing the excess phosphorous above the stoichiometric amount, a method has been proposed in which an oxide in an amount that reacts with the excess phosphorus is added and calcined again (see JP-A-5-171143). There is a disadvantage that the reaction is likely to be heterogeneous due to body mixing.
The present invention newly provides a method for producing a rare earth element phosphate having a low stoichiometric excess phosphorus content, which has solved the above disadvantages.
【0004】[0004]
【課題を解決するための手段】本発明者は、上記課題を
解決するため鋭意検討し本発明を完成させた。すなわ
ち、本発明の要旨は、燐酸水溶液と希土類元素酸性水溶
液との反応による希土類元素燐酸塩の製造において、予
め蓚酸または水溶性蓚酸塩を溶解した燐酸水溶液と希土
類元素酸性水溶液を撹拌下混合し、生成した沈澱を固液
分離して水洗した後、酸化性雰囲気中にて600〜13
00℃で焼成することを特徴とする方法であり、さらに
燐酸水溶液と予め蓚酸または水溶性蓚酸塩を溶解した希
土類元素酸性水溶液を撹拌下混合し、生成した沈澱を固
液分離して水洗した後、酸化性雰囲気中にて600〜1
300℃で焼成することを特徴とする化学量論超過燐含
有量の低い希土類元素燐酸塩の製造方法である。Means for Solving the Problems The present inventors diligently studied to solve the above problems and completed the present invention. That is, the gist of the present invention is to produce a rare earth element phosphate by reacting a phosphoric acid aqueous solution and a rare earth element acidic aqueous solution, mixing a phosphoric acid aqueous solution in which oxalic acid or a water-soluble oxalate is dissolved in advance and a rare earth element acidic aqueous solution with stirring, The precipitate formed is separated into solid and liquid and washed with water.
This method is characterized by baking at 00 ° C., and further mixing a phosphoric acid aqueous solution and a rare earth element acidic aqueous solution in which oxalic acid or a water-soluble oxalate is dissolved in advance, and solid-liquid separation of the resulting precipitate, followed by washing with water. 600 to 1 in oxidizing atmosphere
A method for producing a rare earth element phosphate having a low stoichiometric excess phosphorus content, characterized by firing at 300 ° C.
【0005】[0005]
【発明の実施の形態】以下、本発明を詳細に説明する。
希土類元素燐酸塩は、燐酸水溶液と希土類元素の酸性水
溶液を攪拌下混合して沈殿させる。この際、予め燐酸水
溶液中或いは希土類元素の酸性水溶液中に蓚酸または水
溶性蓚酸塩を溶解しておくと、均一に希土類元素蓚酸塩
を含有する希土類元素燐酸塩が生じる。なお、蓚酸は、
両方の溶液に溶解しておくことも可能である。これを焼
成することによって、残留していた化学量論を超過した
過剰の燐分と、希土類元素蓚酸塩の熱分解によって生成
した希土類酸化物が反応して希土類元素燐酸塩に変化
し、蛍光体の原料に好適な化学量論超過燐含有量の低い
希土類元素燐酸塩が安定的に生成する。蓚酸塩を選んだ
のは、熱分解して酸化物となるような希土類化合物の中
で、沈殿反応によって得られ、酸性溶液中でも比較的安
定なためである。本発明では、予め蓚酸または水溶性蓚
酸塩を燐酸水溶液あるいは希土類元素酸性水溶液のどち
らか一方に溶解させておくので、粉体状の酸化物を添加
する場合のような不均一化はなく、均一に希土類元素蓚
酸塩を含有する希土類元素燐酸塩を生じる。BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The rare earth element phosphate is precipitated by mixing a phosphoric acid aqueous solution and an acidic aqueous solution of the rare earth element with stirring. At this time, if oxalic acid or a water-soluble oxalate is previously dissolved in a phosphoric acid aqueous solution or an acidic aqueous solution of a rare earth element, a rare earth element phosphate containing the rare earth element oxalate uniformly is generated. In addition, oxalic acid
It is also possible to dissolve in both solutions. By sintering this, the excess phosphorus exceeding the remaining stoichiometry and the rare earth oxide generated by the thermal decomposition of the rare earth oxalate react to change to the rare earth phosphate, and the phosphor is changed. Rare earth element phosphates having a low stoichiometric excess phosphorus content suitable for the raw material of the present invention are stably formed. The oxalate was selected because it is obtained by a precipitation reaction in a rare earth compound which is thermally decomposed into an oxide, and is relatively stable even in an acidic solution. In the present invention, since oxalic acid or a water-soluble oxalate is previously dissolved in either a phosphoric acid aqueous solution or a rare-earth element acidic aqueous solution, there is no non-uniformity as in the case of adding a powdery oxide, and uniform To form a rare earth phosphate containing a rare earth oxalate.
【0006】水溶性の蓚酸塩としては、蓚酸アンモニウ
ム、蓚酸ナトリウムや蓚酸カリウム等の蓚酸アルカリ金
属塩等が挙げられるが、アルカリ金属による汚染がない
蓚酸アンモニウムが好ましい。蓚酸または水溶性蓚酸塩
の添加量は、化学量論を超過する燐の含有量が沈殿条件
や水洗条件等によって変動するため、予め予備テストと
して蓚酸または水溶性蓚酸塩無添加で希土類元素燐酸塩
を調製し、その条件下での化学量論を超過する燐の含有
量を分析して、これと反応する当量の希土類元素蓚酸塩
に相当する量とする。一般的に、蓚酸または水溶性蓚酸
塩無添加で希土類元素燐酸塩を製造したときの希土類元
素燐酸塩中の化学量論を超過する燐の含有量は、希土類
元素の1〜10モル%程度であるから、該過剰な燐と反
応する希土類元素蓚酸塩に相当する蓚酸または水溶性蓚
酸塩は、おおよそ希土類元素の1.5〜15.0モル%
程度となる。しかし、実際には蓚酸または水溶性蓚酸塩
の添加量は前記予備テストによって決定するのがよく、
上記の数値は大体の目安である。例えば、大過剰の燐酸
中で沈殿させる場合などは、燐の残存量が希土類元素の
10モル%を超えるので、蓚酸または水溶性蓚酸塩を1
5モル%以上添加する必要がある。Examples of the water-soluble oxalate include ammonium oxalate, alkali metal oxalates such as sodium oxalate and potassium oxalate, etc., and ammonium oxalate which is free from contamination by alkali metals is preferred. As the amount of oxalic acid or water-soluble oxalate added, the phosphorus content exceeding the stoichiometry varies depending on the precipitation conditions, washing conditions, etc. Is prepared and the phosphorus content in excess of the stoichiometry under the conditions is analyzed to the amount corresponding to the equivalent of the rare earth oxalate reacting therewith. Generally, when a rare earth element phosphate is produced without adding oxalic acid or a water-soluble oxalate, the content of phosphorus exceeding the stoichiometry in the rare earth element phosphate is about 1 to 10 mol% of the rare earth element. Therefore, oxalic acid or a water-soluble oxalate corresponding to the rare earth element oxalate reacting with the excess phosphorus is approximately 1.5 to 15.0 mol% of the rare earth element.
About. However, in practice, the amount of oxalic acid or water-soluble oxalate added is preferably determined by the preliminary test.
The above numbers are approximate. For example, in the case of precipitating in a large excess of phosphoric acid, the residual amount of phosphorus exceeds 10 mol% of the rare earth element.
It is necessary to add 5 mol% or more.
【0007】また、燐酸/希土類元素のモル比が1.5
〜5.0、更には2.0〜3.0となるように、各水溶
液の濃度、容量を調整するのが好ましい。燐酸/希土類
元素のモル比は大きいほど収率が大きくなる傾向があ
り、1.5未満では収率が低過ぎ、5.0を超えても収
率はそれ以上は大きくならない。そして、混合後の水溶
液中の希土類元素濃度(沈殿やイオンも含む)が0.1
モル/リットル未満となるように、各水溶液の濃度、容
量を調整するのが好ましい。混合後の水溶液中の希土類
元素濃度は大きいほど収率が小さくなる傾向があり、
0.1モル/リットル以上では収率が低過ぎ生産性が悪
い。Further, the molar ratio of phosphoric acid / rare earth element is 1.5
It is preferable to adjust the concentration and volume of each aqueous solution so as to be 5.0 to 5.0, and more preferably 2.0 to 3.0. The yield tends to increase as the molar ratio of phosphoric acid / rare earth element increases, and if it is less than 1.5, the yield is too low, and if it exceeds 5.0, the yield does not increase any more. Then, the concentration of the rare earth element (including precipitates and ions) in the aqueous solution after mixing is 0.1.
It is preferable to adjust the concentration and volume of each aqueous solution so as to be less than mol / liter. The yield tends to decrease as the rare earth element concentration in the aqueous solution after mixing increases,
If it is 0.1 mol / liter or more, the yield is too low and the productivity is poor.
【0008】希土類元素酸性水溶液のpHは0.5以上
4以下が適当である。0.5より低いと収率が悪く、4
より高いと溶液加温時などに加水分解による希土類水酸
化物の沈殿が析出する可能性がある。燐酸水溶液と希土
類元素酸性水溶液の温度はそれぞれ任意でよいが、混合
終了後一度は70℃以上沸点以下の温度を経過するよう
にする。経過温度が低いほど収率が小さくなる傾向があ
り、70℃未満では収率が低過ぎ生産性が悪い。次に、
得られた沈澱を濾過等の方法により固液分離した後、水
洗する。水洗条件は前述の蓚酸の添加量を決めた予備テ
ストの条件に合わせる。次いで、得られた沈澱を大気中
のような酸化性雰囲気中にて30分以上焼成する。焼成
温度は、希土類元素蓚酸塩と過剰の燐分が反応して希土
類元素燐酸塩を生じるように600〜1300℃、好ま
しくは600〜1000℃とする。600℃未満では未
反応物が残存し、1300℃を超えると粒子同士の焼結
などが起こるため好ましくない。The pH of the acidic aqueous solution of the rare earth element is suitably 0.5 or more and 4 or less. If it is lower than 0.5, the yield is poor and 4
If the temperature is higher, precipitation of the rare earth hydroxide due to hydrolysis may occur at the time of heating the solution. The temperature of the phosphoric acid aqueous solution and the temperature of the rare earth element acidic aqueous solution may be arbitrarily set. The yield tends to be lower as the elapsed temperature is lower, and if it is lower than 70 ° C., the yield is too low and the productivity is poor. next,
The obtained precipitate is subjected to solid-liquid separation by a method such as filtration, and then washed with water. The washing conditions are adjusted to the conditions of the preliminary test in which the amount of oxalic acid is determined. Next, the obtained precipitate is baked for 30 minutes or more in an oxidizing atmosphere such as the air. The firing temperature is set to 600 to 1300 ° C., preferably 600 to 1000 ° C. so that the rare earth element oxalate reacts with excess phosphorus to form a rare earth element phosphate. If the temperature is lower than 600 ° C., unreacted substances remain.
【0009】本発明によれば、得られる希土類元素燐酸
塩中の燐/希土類元素の原子比を1.00〜1.02の
範囲にできる。この比が1.00より小さいと蛍光体に
したときの輝度が極端に落ち、1.02を超えると、前
述のようにスラリーのゲル化の原因となり、水銀と反応
して輝度の低下を引き起こす。According to the present invention, the atomic ratio of phosphorus / rare earth element in the resulting rare earth element phosphate can be in the range of 1.00 to 1.02. If the ratio is less than 1.00, the brightness of the phosphor becomes extremely low, and if it exceeds 1.02, it causes gelation of the slurry as described above and reacts with mercury to lower the brightness. .
【0010】本発明が適用される希土類元素は、イット
リウムを含む原子番号51〜71の元素からなる群から
選択される1種または2種以上の混合希土類元素で、C
e−Tb、Nd−Yb、La−Ce−Tbなどであり、
塩酸塩、硝酸塩等として水溶液を調製する。リチウムを
含有させる化合物は、Nd−Yb燐酸塩とリチウム化合
物と燐酸アンモニウムを固相で反応させてLi−Nd−
Yb燐酸塩とする。混合希土類元素燐酸塩を製造する場
合は、各希土類元素の混合比が所定値になるように各希
土類元素の酸性水溶液を所定量混合して、燐酸/希土類
元素のモル比が1.5〜5.0、かつ混合後の液中の全
体の希土類元素濃度が0.1モル/リットル未満となる
ように各水溶液の濃度、容量を調整する。The rare earth element to which the present invention is applied is one or more kinds of mixed rare earth elements selected from the group consisting of elements having atomic numbers 51 to 71 containing yttrium.
e-Tb, Nd-Yb, La-Ce-Tb, etc.
An aqueous solution is prepared as a hydrochloride, nitrate or the like. The compound containing lithium is obtained by reacting Nd-Yb phosphate, lithium compound and ammonium phosphate in a solid phase to obtain Li-Nd-
Yb phosphate. When producing a mixed rare earth element phosphate, a predetermined amount of an acidic aqueous solution of each rare earth element is mixed so that the mixing ratio of each rare earth element becomes a predetermined value, and the molar ratio of phosphoric acid / rare earth element is 1.5 to 5 0.0 and the concentration and volume of each aqueous solution are adjusted so that the total rare earth element concentration in the mixed liquid is less than 0.1 mol / liter.
【0011】[0011]
【実施例】以下、本発明を実施例と比較例を挙げて具体
的に説明するが、本発明はこれらに何等限定されるもの
ではない。 (実施例1)0.4モル/リットルに調整した燐酸水溶
液500mlに蓚酸8.0×10-3モルを溶解し、85
℃に加熱した。希土類元素濃度を0.15モル/リット
ル、pH=1.5に調整した硝酸ガドリニウム水溶液5
00mlを85℃に加熱した。なお、上記の蓚酸の添加
量は、予め蓚酸を添加しない以外は本実施例と同様の条
件で予備テストを行い、ガドリニウム燐酸塩中の燐/ガ
ドリニウムの原子比が1.071であったことから決定
した。撹拌しながら、蓚酸含有燐酸水溶液に硝酸ガドリ
ニウム水溶液を2分で加えて反応させた。得られた沈澱
を吸引濾過した後、1リットルの純水で洗浄した。洗浄
した沈澱をルツボに入れ、大気中にて700℃で2時間
焼成した。得られたガドリニウム燐酸塩中の燐/ガドリ
ニウムの原子比は1.015であった。また、ガドリニ
ウム燐酸塩の収率は95%であった。EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these. Example 1 8.0 × 10 −3 mol of oxalic acid was dissolved in 500 ml of a phosphoric acid aqueous solution adjusted to 0.4 mol / l,
Heated to ° C. Gadolinium nitrate aqueous solution 5 adjusted to a rare earth element concentration of 0.15 mol / liter and pH = 1.5
00 ml was heated to 85 ° C. A preliminary test was performed under the same conditions as in the present example except that oxalic acid was not added in advance, and the atomic ratio of phosphorus / gadolinium in gadolinium phosphate was 1.071. Decided. While stirring, an aqueous solution of gadolinium nitrate was added to the aqueous solution of phosphoric acid containing oxalic acid in 2 minutes to cause a reaction. The obtained precipitate was filtered by suction and washed with 1 liter of pure water. The washed precipitate was put in a crucible and calcined at 700 ° C. for 2 hours in the atmosphere. The atomic ratio of phosphorus / gadolinium in the resulting gadolinium phosphate was 1.015. The yield of gadolinium phosphate was 95%.
【0012】(実施例2)0.4モル/リットルに調整
した燐酸水溶液500mlを85℃に加熱した。希土類
元素濃度を0.15モル/リットル、pH=1.2に調
整した硝酸イッテルビウム水溶液500mlに蓚酸1.
0×10-2モルを溶解し、85℃に加熱した。なお、上
記の蓚酸の添加量は、予め蓚酸を添加しない以外は本実
施例と同様の条件で予備テストを行い、イッテルビウム
燐酸塩中の燐/イッテルビウムの原子比が1.089で
あったことから決定した。撹拌しながら、燐酸水溶液に
蓚酸含有硝酸イッテルビウム水溶液を2分で加えて反応
させた。得られた沈澱を吸引濾過した後、1リットルの
純水で洗浄した。洗浄した沈澱をルツボに入れ、大気中
にて700℃で2時間焼成した。得られたイッテルビウ
ム燐酸塩中の燐/イッテルビウムの原子比は1.005
であった。また、イッテルビウム燐酸塩の収率は94%
であった。Example 2 500 ml of a phosphoric acid aqueous solution adjusted to 0.4 mol / l was heated to 85 ° C. Oxalic acid was added to 500 ml of an aqueous ytterbium nitrate solution adjusted to a rare earth element concentration of 0.15 mol / liter and pH = 1.2.
0 × 10 −2 mol was dissolved and heated to 85 ° C. A preliminary test was conducted under the same conditions as in this example except that oxalic acid was not added in advance, and the atomic ratio of phosphorus / ytterbium in ytterbium phosphate was 1.089. Decided. While stirring, an aqueous solution of ytterbium nitrate containing oxalic acid was added to the aqueous solution of phosphoric acid for 2 minutes to cause a reaction. The obtained precipitate was filtered by suction and washed with 1 liter of pure water. The washed precipitate was put in a crucible and calcined at 700 ° C. for 2 hours in the atmosphere. The atomic ratio of phosphorus / ytterbium in the obtained ytterbium phosphate is 1.005.
Met. The yield of ytterbium phosphate was 94%.
Met.
【0013】(実施例3)0.2モル/リットルに調整
した燐酸水溶液500mlに蓚酸3.75×10-3モル
を溶解し、80℃で加熱した。希土類元素濃度を0.1
モル/リットル、pH=2.0に調整したLa、Ceお
よびTbを含む混合希土類元素硝酸塩水溶液(各希土類
元素のモル比はLa:Ce:Tb=5:4:1)500
mlを80℃に加熱した。なお、上記の蓚酸の添加量
は、予め蓚酸を添加しない以外は本実施例と同様の条件
で予備テストを行い、混合希土類元素燐酸塩中の燐/希
土類元素の原子比が1.050であったことから決定し
た。撹拌しながら、蓚酸含有燐酸水溶液に混合希土類元
素硝酸塩水溶液を1分で加えて反応させた。得られた沈
澱を吸引濾過した後、1リットルの純水で洗浄した。洗
浄した沈澱をルツボに入れ、大気中にて700℃で2時
間焼成した。得られた混合希土類元素燐酸塩中の燐/希
土類元素の原子比は1.009であった。また、混合希
土類元素燐酸塩の収率は98%であった。Example 3 3.75 × 10 −3 mol of oxalic acid was dissolved in 500 ml of a phosphoric acid aqueous solution adjusted to 0.2 mol / l, and heated at 80 ° C. Rare earth element concentration 0.1
A mixed rare earth element nitrate aqueous solution containing La, Ce and Tb adjusted to mol / liter and pH = 2.0 (molar ratio of each rare earth element is La: Ce: Tb = 5: 4: 1) 500
ml was heated to 80 ° C. A preliminary test was carried out under the same conditions as in this example except that oxalic acid was not added in advance, and the atomic ratio of phosphorus / rare earth element in the mixed rare earth element phosphate was 1.050. It was decided from that. While stirring, the mixed rare earth element nitrate aqueous solution was added to the oxalic acid-containing aqueous phosphoric acid solution for 1 minute to cause a reaction. The obtained precipitate was filtered by suction and washed with 1 liter of pure water. The washed precipitate was put in a crucible and calcined at 700 ° C. for 2 hours in the atmosphere. The atomic ratio of phosphorus / rare earth element in the obtained mixed rare earth element phosphate was 1.009. Further, the yield of the mixed rare earth element phosphate was 98%.
【0014】(実施例4)0.2モル/リットルに調整
した燐酸水溶液500mlに蓚酸8.0×10-3モルを
溶解し、85℃に加熱した。希土類元素濃度を0.15
モル/リットル、pH=1.2に調整した硝酸ガドリニ
ウム水溶液500mlを85℃に加熱した。なお、上記
の蓚酸の添加量は、予め蓚酸を添加しない以外は本実施
例と同様の条件で予備テストを行い、ガドリニウム燐酸
塩中の燐/ガドリニウムの原子比が1.071であった
ことから決定した。撹拌しながら、蓚酸含有燐酸水溶液
に硝酸ガドリニウム水溶液を2分で加えて反応させた。
得られた沈澱を吸引濾過した後、1リットルの純水で洗
浄した。洗浄した沈澱をルツボに入れ、大気中にて70
0℃で2時間焼成した。得られたガドリニウム燐酸塩中
の燐/ガドリニウムの原子比は1.010であった。ま
た、ガドリニウム燐酸塩の収率は85%であった。Example 4 8.0 × 10 -3 mol of oxalic acid was dissolved in 500 ml of a phosphoric acid aqueous solution adjusted to 0.2 mol / l, and heated to 85 ° C. Rare earth element concentration 0.15
500 ml of an aqueous solution of gadolinium nitrate adjusted to mol / liter and pH = 1.2 was heated to 85 ° C. A preliminary test was conducted under the same conditions as in this example except that oxalic acid was not added in advance, and the atomic ratio of phosphorus / gadolinium in the gadolinium phosphate was 1.071. Decided. While stirring, an aqueous solution of gadolinium nitrate was added to the aqueous solution of phosphoric acid containing oxalic acid in 2 minutes to cause a reaction.
The obtained precipitate was filtered by suction and washed with 1 liter of pure water. The washed precipitate is put into a crucible, and the
It was baked at 0 ° C. for 2 hours. The atomic ratio of phosphorus / gadolinium in the resulting gadolinium phosphate was 1.010. The yield of gadolinium phosphate was 85%.
【0015】(実施例5)0.6モル/リットルに調整
した燐酸水溶液500mlに蓚酸1.5×10-2モルを
溶解し、85℃に加熱した。希土類元素濃度を0.3モ
ル/リットル、pH=0.9に調整した硝酸ガドリニウ
ム水溶液500mlを85℃に加熱した。なお、上記の
蓚酸の添加量は、予め蓚酸を添加しない以外は本実施例
と同様の条件で予備テストを行い、ガドリニウム燐酸塩
中の燐/ガドリニウムの原子比が1.067であったこ
とから決定した。撹拌しながら、蓚酸含有燐酸水溶液に
硝酸ガドリニウム水溶液を2分で加えて反応させた。得
られた沈澱を吸引濾過した後、1リットルの純水で洗浄
した。洗浄した沈澱をルツボに入れ、大気中にて700
℃で2時間焼成した。得られたガドリニウム燐酸塩中の
燐/ガドリニウムの原子比は1.010であった。ま
た、ガドリニウム燐酸塩の収率は70%であった。Example 5 1.5 × 10 -2 mol of oxalic acid was dissolved in 500 ml of a phosphoric acid aqueous solution adjusted to 0.6 mol / l, and heated to 85 ° C. 500 ml of an aqueous solution of gadolinium nitrate adjusted to a rare earth element concentration of 0.3 mol / liter and pH = 0.9 was heated to 85 ° C. A preliminary test was conducted under the same conditions as in this example except that oxalic acid was not added in advance, and the atomic ratio of phosphorus / gadolinium in gadolinium phosphate was 1.067. Decided. While stirring, an aqueous solution of gadolinium nitrate was added to the aqueous solution of phosphoric acid containing oxalic acid in 2 minutes to cause a reaction. The obtained precipitate was filtered by suction and washed with 1 liter of pure water. The washed precipitate is placed in a crucible, and the
Calcination was performed at 2 ° C for 2 hours. The atomic ratio of phosphorus / gadolinium in the resulting gadolinium phosphate was 1.010. The yield of gadolinium phosphate was 70%.
【0016】(実施例6)0.4モル/リットルに調整
した燐酸水溶液500mlに蓚酸8.0×10-3モルを
溶解し、60℃に加熱した。希土類元素濃度を0.2モ
ル/リットル、pH=1.0に調整した硝酸ガドリニウ
ム水溶液500mlを60℃に加熱した。なお、上記の
蓚酸の添加量は、予め蓚酸を添加しない以外は本実施例
と同様の条件で予備テストを行い、ガドリニウム燐酸塩
中の燐/ガドリニウムの原子比が1.053であったこ
とから決定した。撹拌しながら、蓚酸含有燐酸水溶液に
硝酸ガドリニウム水溶液を2分で加えて反応させた。得
られた沈澱を吸引濾過した後、1リットルの純水で洗浄
した。洗浄した沈澱をルツボに入れ、大気中にて700
℃で2時間焼成した。得られたガドリニウム燐酸塩中の
燐/ガドリニウムの原子比は1.005であった。ま
た、ガドリニウム燐酸塩の収率は75%であった。Example 6 8.0 × 10 −3 mol of oxalic acid was dissolved in 500 ml of a phosphoric acid aqueous solution adjusted to 0.4 mol / l, and heated to 60 ° C. 500 ml of an aqueous solution of gadolinium nitrate adjusted to a rare earth element concentration of 0.2 mol / liter and pH = 1.0 was heated to 60 ° C. A preliminary test was performed under the same conditions as in this example except that oxalic acid was not added in advance, and the atomic ratio of phosphorus / gadolinium in gadolinium phosphate was 1.053. Decided. While stirring, an aqueous solution of gadolinium nitrate was added to the aqueous solution of phosphoric acid containing oxalic acid in 2 minutes to cause a reaction. The obtained precipitate was filtered by suction and washed with 1 liter of pure water. The washed precipitate is placed in a crucible, and the
Calcination was performed at 2 ° C for 2 hours. The atomic ratio of phosphorus / gadolinium in the resulting gadolinium phosphate was 1.005. The yield of gadolinium phosphate was 75%.
【0017】(比較例1)燐酸水溶液中に蓚酸を添加し
ない以外は、実施例3と同様の条件で混合希土類元素燐
酸塩を製造した。得られた混合希土類元素燐酸塩中の燐
/希土類元素の原子比は1.050であった。また、混
合希土類元素燐酸塩の収率は99%であった。Comparative Example 1 A mixed rare earth element phosphate was produced under the same conditions as in Example 3 except that oxalic acid was not added to the phosphoric acid aqueous solution. The phosphorus / rare earth element atomic ratio in the obtained mixed rare earth element phosphate was 1.050. Further, the yield of the mixed rare earth element phosphate was 99%.
【0018】[0018]
【発明の効果】本発明によれば、蛍光体の原料に好適な
化学量論超過燐含有量の低い希土類元素燐酸塩が得ら
れ、産業上その利用価値は極めて高い。According to the present invention, a rare earth element phosphate having a low stoichiometric excess phosphorus content suitable for a raw material of a phosphor can be obtained, and its industrial value is extremely high.
Claims (2)
応による希土類元素燐酸塩の製造において、予め蓚酸ま
たは水溶性蓚酸塩を溶解した燐酸水溶液と希土類元素酸
性水溶液を撹拌下混合し、生成した沈澱を固液分離して
水洗した後、酸化性雰囲気中にて600〜1300℃で
焼成することを特徴とする化学量論超過燐含有量の低い
希土類元素燐酸塩の製造方法。In the production of a rare earth element phosphate by reacting a phosphoric acid aqueous solution with a rare earth element acidic aqueous solution, a phosphoric acid aqueous solution in which oxalic acid or a water-soluble oxalate is dissolved in advance and a rare earth element acidic aqueous solution are mixed with stirring to form a precipitate formed. A solid-liquid separation, washing with water and baking at 600 to 1300 ° C. in an oxidizing atmosphere, wherein the rare earth element phosphate having a low phosphorous content exceeding the stoichiometric amount is obtained.
応による希土類元素燐酸塩の製造において、燐酸水溶液
と予め蓚酸または水溶性蓚酸塩を溶解した希土類元素酸
性水溶液を攪拌下混合し、生成した沈澱を固液分離して
水洗した後、酸化性雰囲気中にて600〜1300℃で
焼成することを特徴とする化学量論超過燐含有量の低い
希土類元素燐酸塩の製造方法。2. In the production of a rare earth element phosphate by the reaction of a phosphoric acid aqueous solution and a rare earth element acidic aqueous solution, the phosphoric acid aqueous solution and a rare earth element acidic aqueous solution in which oxalic acid or a water-soluble oxalate is dissolved in advance are mixed with stirring, and the resulting precipitate is formed. A solid-liquid separation, washing with water and baking at 600 to 1300 ° C. in an oxidizing atmosphere, wherein the rare earth element phosphate having a low phosphorous content exceeding the stoichiometric amount is obtained.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP18496197A JPH1087309A (en) | 1996-07-10 | 1997-07-10 | Production of rare earth element phosphate having small excess amount of phosphorus than stoichiometric amount |
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP18046096 | 1996-07-10 | ||
JP8-180460 | 1996-07-10 | ||
JP18496197A JPH1087309A (en) | 1996-07-10 | 1997-07-10 | Production of rare earth element phosphate having small excess amount of phosphorus than stoichiometric amount |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH1087309A true JPH1087309A (en) | 1998-04-07 |
Family
ID=26499979
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP18496197A Pending JPH1087309A (en) | 1996-07-10 | 1997-07-10 | Production of rare earth element phosphate having small excess amount of phosphorus than stoichiometric amount |
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Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2010507551A (en) * | 2006-10-20 | 2010-03-11 | エイエムアール インターナショナル コーポレーション | Method for producing rare earth-containing phosphate |
JP2011046588A (en) * | 2009-07-31 | 2011-03-10 | Canon Inc | Method for producing ytterbium phosphate fine particle |
-
1997
- 1997-07-10 JP JP18496197A patent/JPH1087309A/en active Pending
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2010507551A (en) * | 2006-10-20 | 2010-03-11 | エイエムアール インターナショナル コーポレーション | Method for producing rare earth-containing phosphate |
JP2011046588A (en) * | 2009-07-31 | 2011-03-10 | Canon Inc | Method for producing ytterbium phosphate fine particle |
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